1. Field of the Invention
The invention relates to antimicrobial compositions which comprise a synergistic combination of a product derived by reacting formaldehyde with an alcohol; and a tetrahydro-2H-1,3,5-thiadiazine-2-thione, useful in controlling the propagation and growth of bacteria and fungi in a variety of industrial fluids and cosmetic and pharmaceutical preparations.
2. Description of the Prior Art
The use of products derived from the reaction of aldehydes with alcohols, for example, such as the formal of benzyl alcohol or the acetals of glycols and glycol ethers, for the preservation and disinfection of industrial fluids is known. Since these compounds are deficient in their microbiocidal activity with respect to fungi and yeasts, they are usually combined with another active ingredient, pentachlorophenol. However, due to the toxicity to warm blooded animals of pentachlorophenol, and the fact that chlorinated phenols are not readily biodegradable, there is a great need for compositions, comprising mixtures of active ingredients, which have a broad spectrum of antimicrobial effectiveness, including effectiveness against various fungi, without having disadvantages such as those associated with the chlorinated phenols.
The fungicidal effectiveness of 3,5-disubstituted-tetrahydro-2H-thiadiazine-2-thiones against certain fungi is known. It is also known that tetrahydro-2-H-thiadiazine-2-thiones, when employed in cooling lubricants together with reducing agents, can undergo reduction with the formation of colloidal sulfur, an undesirable result.